Software-based color-grading applications integrated with concurrent HD finishing workflows offer the potential of highly differentiated creative appearances and greater facility productivity. The net result is increased efficiency and profitability. A concurrent workflow describes a methodology for performing a number of post-production functions at the same time, using the same media. For the purpose of this document, the functions discussed include color grading, visual effects design, and finishing.

Advanced creative tools in software systems

The television industry is poised to benefit from a new generation of tools for color grading that offer a wide range of creative advantages. Most high-profile movies today take advantage of software-based grading (the digital intermediates or DI process) to define the final look of the film. This process is considered as carefully as editing or special effects. These tools are now also available for television workflows.

By offering the ability to apply and animate multiple layers of primary and secondary correction to an image, creative color grading enables the colorists, directors of photography, and art directors to work with an image like a painter, subtly and profoundly adjusting the elements of light and color until the creative vision is achieved.

Workflow efficiency - Requirements of a concurrent workflow

When it comes to workflow, there is no one way of working. Every client has unique requirements and the ideal solution should be open and flexible enough to allow for facility customization. Most workflow solutions should be based on open concepts, open application programming interfaces (APIs), and standard connectivity in order to add the most value, in terms of creativity and efficiency, to a particular project. The following requirements must be considered:

Maximizing creative session productivity. One of the first considerations is how to maximize artistic output while maintaining the greatest amount of flexibility to handle back-end processes such as video I/O, project setup, archiving, and rendering. Tasks related to rendering and archiving, for instance, are very difficult to charge back to clients, and therefore should be offloaded to more cost-effective dedicated assistant systems. It is understood that creative tasks such as grading, visual effects, and finishing, which take place in the more expensive suites, are billable. By offloading noncreative tasks to back-room systems, the artists in the creative suites can focus on the kind of work that generates revenue (as well as the kind of work they enjoy).

Source grading and in-context final grade. Of course, while focusing on color grading, the colorist must have a concurrent color workflow to modify the sources. This allows the material to be graded as soon as it is transferred into a digital format, as well as the creation of an in-context final grade to focus on continuity and look developed. C-mode sorting is certainly needed, as are A-mode grading capabilities. Software systems that work from digital files also have the advantage of enabling a nonlinear workflow. Multiple files can be graded simultaneously, regardless of the reel or the position in a timeline.

Nonlinear workflow and scheduling flexibility. One of the major downsides of a traditional grading workflow is that finishing cannot begin until the media is graded, and digitized into the finishing environment. Concurrent workflows do not have this constraint. As a result, the facility has the added flexibility to start a given process based on suite/system availability. If the frames are digitized on to centrally available storage, and the colorist is in a session with another client, the finishing artist can start working from the ungraded sources. Provided that finishing is nondestructive, no time will be wasted. Once the colorist is available and generates the final renders, the finishing system should simply be able to point to new media and instantly re-conform to the graded images. This is easy, provided that basic image metadata, such as the source reel name and time code, is unchanged by renders.

In the best case scenario, both the finishing artist and the colorist are available to begin working at the same time. In a truly concurrent environment, no duplication of media is needed. Both systems can work using the same media with no sacrifice in terms of system performance and interactivity. Media duplication should be kept to a minimum, as it requires additional storage, time-consuming network transfers (which can also affect facility network performance), and can even lead to confusion regarding which version is the correct version.

Working in a shared environment. Shared storage and high-speed networks, capable of serving up images to all requesting systems as needed, must form the backbone of a concurrent workflow. Of course, a storage area network (SAN) connected to a client workstation via a fiber channel is a viable option, but may prove to be prohibitively expensive, especially for smaller facilities. Other options need to be available. Commonly, each system in a facility has its own direct-attached storage array that enables a high degree of interactivity and real-time playback of high-resolution images. Yet high performance disk arrays (based on 4G-bit technology) offer far more bandwidth than is needed for a single system. In fact, a single disk array can stream multiple HD streams simultaneously. Coupled with a high-speed network, such as that provided by 4x Infiniband, multiple networked systems could pull data from one single disk array. While a SAN offers an elegant solution, it is not the only option for concurrent environments based on two to three systems.

Integrating visual effects. In any facility, visual effects and compositing are often handled independently from (and concurrently with) finishing, so it is important that shot-based effects work can be easily integrated with the workflow. Additional complexity is added, but it is very common for visual effects iteration to result in last-minute changes. The ease with which newly shot versions are integrated back to the final timeline, either at the finishing stage or during the final grade, can be the difference between successful completion of a project or missing a deadline.

Providing final in-context grade

Software-based color-grading systems provide the ability to offer a DI-style final in-context color grade to clients. This session usually takes place in a dark grading theater and allows the clients to experience the work in all its glory, projected digitally on to a large screen. This ability is changing both the client experience as well as expectations about what it means to attend a grading session, and provides a competitive advantage.

Color management. The last consideration for the concurrent workflow relates to color management. Generally, color management is used in facilities specializing in film post-production as it offers a reliable way to accurately reproduce, on a given display device, how digital images will appear when printed to film. However, a robust color-management system has important advantages in a concurrent workflow. On any given concurrent project, work may happen on the same shot at the same time in three or more different suites (for instance, grading, effects, and finishing). A client could literally walk from one suite to another and follow a project's progress. If the images do not match from one suite to the next, this could engender uncertainty and lead to a lack of confidence in the facility process.

An out-of-the box color-management system can do away with this concern, provided that each necessary system in the facility can use a common set of display look-up tables (3D LUTs) that account for the display device (DLP, LCD, or CRT) and the destination format (for instance, HD REC-709, SD ITU-601, or RGB). Thus, each system's images would look the same within the constraints of its respective calibrated display device. Clients moving between suites would see matching images in each room.

Benefits of concurrent color workflow. Post-production facilities are adopting software systems for creative color grading even though there are incumbent solutions that have been used successfully in the market for many years. There are a number of reasons for this change:

• In a world of increasingly competitive project bidding, facilities are looking for ways of standing out from the crowd. The creativity of talented artists remains one of the best ways to attract clients, and fostering that creativity is paramount to success.
• Creative color grading requires a lower capital investment, which therefore allows a facility to compete more easily for a project without the chance of losing money.
• Increases in digital acquisition are making it possible to take on color-grading projects without expensive film transfer infrastructure.
• Adding software-based grading systems allows a facility to expand the list of services offered. Given that many software-based grading systems are also used in feature film digital intermediates, a facility can begin developing new areas of expertise, and attract new clients in the process.
• Adding software-based grading systems allows a facility to expand the list of services offered. Given that many software-based grading systems are also used in feature film digital intermediates, a facility can begin developing new areas of expertise, and attract new clients in the process.

Most post-production professionals understand that grading is recognized as one of the most highly valued services in post-production. Implementing a concurrent workflow can open the door to compelling new revenue opportunities based on a service that clients already understand and are willing to pay for - highly creative color grading inside a nonlinear visual effects and finishing environment.